Re: [PATCH 27/55] target/arm: Implement MVE VHADD, VHSUB

[Richard Henderson]

On 6/7/21 9:57 AM, Peter Maydell wrote:
> Implement MVE VHADD and VHSUB insns, which perform an addition
> or subtraction and then halve the result.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>   target/arm/helper-mve.h    | 14 ++++++++++++++
>   target/arm/mve.decode      |  5 +++++
>   target/arm/mve_helper.c    | 25 +++++++++++++++++++++++++
>   target/arm/translate-mve.c |  4 ++++
>   4 files changed, 48 insertions(+)
>
> diff --git a/target/arm/helper-mve.h b/target/arm/helper-mve.h
> index bfe2057592f..7b22990c3ba 100644
> --- a/target/arm/helper-mve.h
> +++ b/target/arm/helper-mve.h
> @@ -118,3 +118,17 @@ DEF_HELPER_FLAGS_4(mve_vabdsw, TCG_CALL_NO_WG, void, env, 
> ptr, ptr, ptr)
>   DEF_HELPER_FLAGS_4(mve_vabdub, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
>   DEF_HELPER_FLAGS_4(mve_vabduh, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
>   DEF_HELPER_FLAGS_4(mve_vabduw, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
> +
> +DEF_HELPER_FLAGS_4(mve_vhaddsb, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
> +DEF_HELPER_FLAGS_4(mve_vhaddsh, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
> +DEF_HELPER_FLAGS_4(mve_vhaddsw, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
> +DEF_HELPER_FLAGS_4(mve_vhaddub, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
> +DEF_HELPER_FLAGS_4(mve_vhadduh, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
> +DEF_HELPER_FLAGS_4(mve_vhadduw, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
> +
> +DEF_HELPER_FLAGS_4(mve_vhsubsb, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
> +DEF_HELPER_FLAGS_4(mve_vhsubsh, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
> +DEF_HELPER_FLAGS_4(mve_vhsubsw, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
> +DEF_HELPER_FLAGS_4(mve_vhsubub, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
> +DEF_HELPER_FLAGS_4(mve_vhsubuh, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
> +DEF_HELPER_FLAGS_4(mve_vhsubuw, TCG_CALL_NO_WG, void, env, ptr, ptr, ptr)
> diff --git a/target/arm/mve.decode b/target/arm/mve.decode
> index 087d3db2a31..241d1c44c19 100644
> --- a/target/arm/mve.decode
> +++ b/target/arm/mve.decode
> @@ -96,6 +96,11 @@ VMIN_U           111 1 1111 0 . .. ... 0 ... 0 0110 . 1 . 1 
> ... 0 @2op
>   VABD_S           111 0 1111 0 . .. ... 0 ... 0 0111 . 1 . 0 ... 0 @2op
>   VABD_U           111 1 1111 0 . .. ... 0 ... 0 0111 . 1 . 0 ... 0 @2op
>   
> +VHADD_S          111 0 1111 0 . .. ... 0 ... 0 0000 . 1 . 0 ... 0 @2op
> +VHADD_U          111 1 1111 0 . .. ... 0 ... 0 0000 . 1 . 0 ... 0 @2op
> +VHSUB_S          111 0 1111 0 . .. ... 0 ... 0 0010 . 1 . 0 ... 0 @2op
> +VHSUB_U          111 1 1111 0 . .. ... 0 ... 0 0010 . 1 . 0 ... 0 @2op
> +
>   # Vector miscellaneous
>   
>   VCLS             1111 1111 1 . 11 .. 00 ... 0 0100 01 . 0 ... 0 @1op
> diff --git a/target/arm/mve_helper.c b/target/arm/mve_helper.c
> index f026a9969d6..5982f6bf5eb 100644
> --- a/target/arm/mve_helper.c
> +++ b/target/arm/mve_helper.c
> @@ -415,3 +415,28 @@ DO_2OP_U(vminu, DO_MIN)
>   
>   DO_2OP_S(vabds, DO_ABD)
>   DO_2OP_U(vabdu, DO_ABD)
> +
> +static inline uint32_t do_vhadd_u(uint32_t n, uint32_t m)
> +{
> +    return ((uint64_t)n + m) >> 1;
> +}
> +
> +static inline int32_t do_vhadd_s(int32_t n, int32_t m)
> +{
> +    return ((int64_t)n + m) >> 1;
> +}
> +
> +static inline uint32_t do_vhsub_u(uint32_t n, uint32_t m)
> +{
> +    return ((uint64_t)n - m) >> 1;
> +}
> +
> +static inline int32_t do_vhsub_s(int32_t n, int32_t m)
> +{
> +    return ((int64_t)n - m) >> 1;
> +}

Use 64-bit inputs and you don't need to replicate these for signed/unsigned. 
But either way,

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~